SMMR-154: Journey

#include <bits/stdc++.h>
using namespace std;
const int INF=2e9;
using pii=pair<long long,int>;
int main(){
    int n,m,k;
    scanf("%d %d %d",&n,&m,&k);
    priority_queue <pii,vector<pii>,greater<pii> > pq;
    vector <pii> g[n+1];
    vector <bool> visited(n+1,false);
    vector <long long> dis(n+1,INF);
    for(int i=0;i<m;i++){
        int u,v;
        long long w;
        scanf("%d %d %d",&u,&v,&w);
        g[u].push_back({v,w});
        g[v].push_back({u,w});
    }
    dis[1] = 0;
    pq.push({dis[1],1});
    while(!pq.empty()){
        int u=pq.top().second,d=pq.top().first;
        pq.pop();
        //if(visited[u]) continue;
        visited[u]=true;

        for(auto vw:g[u]){
            int v,w;
            v=vw.first;
            w=vw.second;
            if(visited[v]==false && dis[u]+w < dis[v]){
                dis[v] = dis[u] + w;
                pq.push({dis[v],v});
            }
        }
    }
    for(int i=n;i>=1;i--){
        if(dis[i]<=k){
            printf("%d",i);
            break;
        }
    }
    return 0;
}